Senior .NET Backend Engineer — Remote, Growth & Impact

Nmbrs BV; Rotterdam; On-site; EUR 50,000 - 67,000; Full time

Benefits offered by this job

Training budget

Vacation days

Remote work (5 weeks)

Job summary

Nmbrs BV in Rotterdam is looking for a Senior Back-end Developer to own, build and scale the core financial engine of our accounting platform. You’ll lead by example in .NET (VB.NET/C#), mentor junior developers, and drive performance and architectural improvements across the stack.

You’ll join Team AO Ops in Nmbrs Accounting, collaborating with cross-functional peers while focusing on robust APIs, scalable services, and maintainable code that their SME clients trust daily.

Qualifications

• At least 4 years of experience as a back-end developer using .NET technologies (VB.NET/C#).
• Experience coaching and mentoring junior developers (e.g. peer reviewing, sharing best practices).
• Strong experience with relational database engines (MSSQL), and with API development (HTTP, REST, .NET Web API).
• Experience with Agile methodologies (Scrum), and with Azure DevOps and/or GitHub.
• An autonomous, analytical mindset and strong organizational skills.

Responsibilities

• Feature development & integration: Work on implementing new features, APIs, system integrations, and data interfaces (with external parties or Visma solutions), ensuring they're efficient, robust, and aligned with user/system needs.
• Code optimization: Optimize and refactor existing codebases, focusing on improving performance, readability, and maintainability.
• Performance enhancement: Optimize business-critical applications for maximum speed and scalability under heavy system load.
• Mentoring & coaching: Provide guidance, peer reviews, and support to less experienced team members, helping them improve their technical skills and grow professionally.
• Team collaboration: Work closely with cross-functional team members and technical stakeholders, fostering effective communication to achieve project goals.

Skills

Back-end development

.NET technologies

Mentoring juniors

Performance optimization

Education

4+ years back-end dev experience

Tools

Azure DevOps

GitHub

REST APIs

Job description

Nmbrs BV in Rotterdam is looking for a Senior Back-end Developer to own, build and scale the core financial engine of our accounting platform. You’ll lead by example in .NET (VB.NET/C#), mentor junior developers, and drive performance and architectural improvements across the stack.

You’ll join Team AO Ops in Nmbrs Accounting, collaborating with cross-functional peers while focusing on robust APIs, scalable services, and maintainable code that their SME clients trust daily.